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[gdb/testsuite] Fix gdb.base/step-over-syscall.exp with -m32

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When executing test-case gdb.base/step-over-syscall.exp with target board
unix/-m32, we run into:
...
(gdb) x/2i $pc^M
=> 0xf7fd5155 <__kernel_vsyscall+5>:    sysenter ^M
   0xf7fd5157 <__kernel_vsyscall+7>:    int    $0x80^M
(gdb) PASS: gdb.base/step-over-syscall.exp: fork: displaced=off: \
  pc before/after syscall instruction
stepi^M
[Detaching after fork from child process 23593]^M
0xf7fd5159 in __kernel_vsyscall ()^M
1: x/i $pc^M
=> 0xf7fd5159 <__kernel_vsyscall+9>:    pop    %ebp^M
(gdb) PASS: gdb.base/step-over-syscall.exp: fork: displaced=off: stepi fork insn
print /x $pc^M
$2 = 0xf7fd5159^M
(gdb) PASS: gdb.base/step-over-syscall.exp: fork: displaced=off: pc after stepi
FAIL: gdb.base/step-over-syscall.exp: fork: displaced=off: \
  pc after stepi matches insn addr after syscall
...

The test tries to verify that after doing a stepi at a syscall insn, the $pc
is matching the insn after the syscall insn.

However, in the case that the syscall insn is "sysenter", the stepi will land
further away, so in this case:
...
   0xf7fd5155 <__kernel_vsyscall+5>:    sysenter ^M
   0xf7fd5157 <__kernel_vsyscall+7>:    int    $0x80^M
   0xf7fd5159 <__kernel_vsyscall+9>:    pop    %ebp^M
...
the stepi will land at 0xf7fd5159 instead of 0xf7fd5157.

Fix this by detecting the sysenter/int sequence and adjusting the expected
pc.

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2021-01-19  Tom de Vries  <tdevries@suse.de>

	* gdb.base/step-over-syscall.exp: Detect and handle sysenter/int
	sequence.
This commit is contained in:
Tom de Vries
2021-01-19 13:31:12 +01:00
parent 0c4e2c6c88
commit 1485212328
2 changed files with 28 additions and 0 deletions
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5
gdb/testsuite/ChangeLog
View File

@@ -1,3 +1,8 @@
2021-01-19 Tom de Vries <tdevries@suse.de>
* gdb.base/step-over-syscall.exp: Detect and handle sysenter/int
sequence.
2021-01-19 Tom de Vries <tdevries@suse.de>
* gdb.arch/i386-mpx.c (main): Drop argc/argv parameter.

23
gdb/testsuite/gdb.base/step-over-syscall.exp
View File

@@ -155,11 +155,34 @@ proc setup { syscall } {
gdb_test_multiple "x/2i \$pc" "pc before/after syscall instruction" {
-re "x/2i .*=> ($hex) .*:.*$syscall_insn.* ($hex) .*:.*$gdb_prompt $" {
set syscall_insn_addr $expect_out(1,string)
set actual_syscall_insn $expect_out(2,string)
set next_insn_addr $expect_out(3,string)
pass $gdb_test_name
}
}
# If we encounter a sequence:
# 0xf7fd5155 <__kernel_vsyscall+5>: sysenter
# 0xf7fd5157 <__kernel_vsyscall+7>: int $0x80
# 0xf7fd5159 <__kernel_vsyscall+9>: pop %ebp
# then a stepi at sysenter will step over the int insn, so make sure
# next_insn_addr points after the int insn.
if { $actual_syscall_insn == "sysenter" } {
set test "pc after sysenter instruction"
set re_int_insn "\[ \t\]*int\[ \t\]\[^\r\n\]*"
set re [multi_line \
"x/2i $hex" \
"\[^\r\n\]* $hex \[^\r\n\]*:$re_int_insn" \
"\[^\r\n\]* ($hex) \[^\r\n\]*:\[^\r\n\]*"]
gdb_test_multiple "x/2i $next_insn_addr" $test {
-re -wrap $re {
set next_insn_addr $expect_out(1,string)
}
-re -wrap "" {
}
}
}
if {[gdb_test "stepi" "x/i .*=>.*" "stepi $syscall insn"] != 0} {
return { -1, -1 }
}